Re: A quick reminder about SHOULD

[DRUMS WG Chair <[e-mail]>]

This subject will be disregarded on the grounds that it makes references to 
a person in a manner which could be considered impolite.  If there is a 
proposed change to the text in draft 12 behind this, make that proposal 
politely under a new subject and we'll see if there's enough support to 
reconsider the issue.

		- DRUMS WG Chair

--On Sunday, July 23, 2000 6:17 +0000 "D. J. Bernstein" <[e-mail]> 
wrote:

> Please remember that the word ``SHOULD'' has a specific definition in
> Klensin's document. It's much stronger than the RFC 1123 ``SHOULD,''
> never mind the English word ``should.''
>
> When RFC 1123 says that every SMTP server ``SHOULD implement EXPN,'' for
> example, here's what it's saying:
>
>    There may exist valid reasons in particular circumstances to not
>    implement EXPN, but the full implications should be understood and
>    the case carefully weighed.
>
> In contrast, when Klensin says that every SMTP server ``SHOULD support
> EXPN,'' here's what he's saying:
>
>    An SMTP server that doesn't support EXPN may interoperate properly,
>    but this will typically be the case only if great care is taken.
>    Consequently, the requirement to support EXPN should be violated only
>    under exceptional and well-understood circumstances.
>
> That's certainly not what RFC 1123 says. RFC 1123 is merely giving some
> bad advice; Klensin is making a patently ridiculous claim about
> interoperability.
>
> You might think at first glance that Klensin's ``SHOULD support EXPN''
> is the same as RFC 1123's ``SHOULD implement EXPN.'' Don't be fooled!
> Klensin made a big change in the definition of ``SHOULD.''
>
> Can we all agree that the spec should recommend against supporting EXPN?
> Perhaps we can't. But the default position, in the absence of consensus,
> is what RFC 1123 said, _not_ what Klensin wants to say.
>
> ---Dan